In the operation of milling machines, lathes and similar metal working tools, a liquid is utilized to cool and lubricate the tools and the metal parts being worked. The liquid also serves to flush away the resulting chips and cuttings. It is desirable for economic reasons to recirculate the liquid, but the chips and cuttings must first be separated from the liquid and then conveyed to a suitable waste receptacle.
Various types of devices have been designed for achieving this result, such as the apparatus disclosed in U.S. Pat. No. 4,052,311, issued Oct. 4, 1977 and entitled "APPARATUS FOR SEPARATING SOLIDS FROM LIQUIDS". This patent discloses the use of a rotating auger on an inclined support for moving solids, such as cuttings and chips, upwardly out of a tank containing the liquid which is being recirculated. Thus, the liquid can drain from the solids and return down the support to the tank. A discharge opening is provided through the inclined support at the upper end thereof, and the solids drop through this opening into a receptacle. The liquid exits the tank by overflowing a substantially horizontal weir edge adjacent the top of the tank, and is then recirculated to the machine tool.
While devices such as those disclosed in U.S. Pat. No. 4,052,311 have proved satisfactory for their intended purposes, they have not proved satisfactory in all respects. Specifically, these devices have a tendency to slow down and/or jam under certain circumstances particularly when certain objects, such as shop rags, drill bits, bolts and hand tools, get into the system. A jam not only presents a possibility of damage to the conveyor and flooding, but necessitates downtime which can substantially increase production costs.
Further, the separating of solids and liquids is sometimes less than satisfactory in these known devices. Specifically, the solids are sometimes conveyed so quickly up the inclined support that they are not fully drained when they pass through the discharge opening into the receptacle. Further if the shop floor on which the conveyor is supported is somewhat uneven, the weir edge may not be substantially horizontal, in which case the flow of the liquid over the weir edge will not be a shallow flow spread uniformly across the edge, but will be a deeper flow concentrated at the lowermost portion of the edge. Smaller solids present in the liquid can easily be carried with the deeper flow over the weir edge, necessitating further filtering of the liquid before it is returned to a collection tank or the sump of the machine.
Accordingly, an object of this invention is to provide a conveyor apparatus for separating solids from liquids and for conveying the solids from a lower to a higher elevation, said apparatus having a housing and conveying mechanism which minimize the possibility of the solids or objects jamming the conveyor and, if jamming does occur, it is quickly detected so as to avoid damage or loss of time.
A further object of the invention is the provision of a conveyor apparatus, as aforesaid, in which as much liquid as possible has been drained from the solids by the time they are discharged from the conveyor.
A further object of the invention is to provide a conveyor apparatus, as aforesaid, in which the weir edge of the tank is adjustable to a position in which it extends substantially horizontally so that the liquid exiting the tank flows over the weir edge with a uniform shallow depth throughout its length.